To deflect an asteroid, paint it white. That’s the idea that made MIT graduate student Sung Wook Paek the winner of the 2012 Move An Asteroid Competition, a contest set up by the United Nations’ Space Generation Advisory Council that sought innovative ways to deflect asteroids. Paek’s plan is to hurl pellets of white paint at an asteroid in order to make it more reflective, meaning that more photons, or particles of light, would bounce off it, rather than being absorbed. Over time, the force of those photonic collisions, combined with the initial force of the paintballs, would be enough, Paek thinks, to move the asteroid off its path toward Earth.
Current ideas for avoiding asteroids include blasting them with nuclear bombs, fastening rockets to them, using the gravity of a nearby spacecraft to drag them off course, and driving spacecraft into them. The European Space Agency plans to test that last approach in the next few years with their Don Quixote project, in which a massive spacecraft will crash into an asteroid and another spacecraft would observe and record the damage. One of the potential targets is Apophis, a 27-gigaton asteroid on which Paek did his calculations for the paintball approach, scheduled to come near Earth in 2029 and in 2036.
Paek thinks it would take 20 years’ of solar pressure to change the asteroid’s course with his approach, so perhaps Don Quixote will do the work faster on its own. But we can at least fantasize about sending the Man of La Mancha out with paintballs.
Image of asteroid Eros via NASA/JPL/JHUAPL